1. Field of the Invention
The present invention relates to a head unit used for discharging a liquid (ink or EL (electroluminescence) display material) toward a substrate from a liquid head so as to manufacture display device panels containing color filters, EL display devices, etc., an apparatus for manufacturing panels for display devices containing color filters, EL display devices, etc., using the head unit, the manufacturing method thereof, manufacturing method for liquid crystal display devices having color filters, and devices having the liquid crystal display devices.
2. Description of the Related Art
Liquid discharging heads (ink jet heads) can be freely controlled as to the position and amount of liquid (ink) discharged, and accordingly are not only used for common printing purposes, but are further applied to various industries, primarily color filter manufacturing. The following is a description of color filter manufacturing with the ink jet method, which is a representative usage of the present invention.
Advancements in personal computers, particularly in portable personal computers, have led to an increase in liquid crystal displays, particularly in color liquid crystal displays. However, the cost of liquid crystal displays needs to be reduced for even further widespread use, and there is increasing demand for reduction in the cost of color liquid crystal displays, which tend to be more expensive than other display devices because of their quality. Heretofore, various attempts have been made to satisfy the above demands for reductions in cost while satisfying the required properties of the color filter, but no method has yet been established which satisfies all demands. The following is a description of several color filter manufacturing methods.
A first color filter manufacturing method is the dyeing method. The dyeing method involves coating a glass substrate with a water-soluble polymer material, which is the dyeing material, and the water-soluble polymer material is patterned into a desired form by photolithography, following which the obtained pattern is dipped in a dye bath so as to obtain a colored pattern. This process is performed three times, thereby obtaining a color filter layer of R (red), G (green), and B (blue) on the glass substrate.
A second color filter manufacturing method is the pigment dispersion method, which has come to be used most widely in recent years. The pigment dispersion method involves forming a photosensitive resin layer wherein pigment is dispersed on a glass substrate, and patterning this layer, thereby obtaining a monochromatic pattern. This is repeated once for each color, for a total of three times, thereby forming an RGB color filter layer.
A third color filter manufacturing method is the electrocoating method. The electrocoating method involves patterning transparent electrodes on a glass substrate, following which the glass substrate is dipped in an electrocoating paint fluid containing pigment, resin, electrocoating fluid, etc., so as to perform electrocoating of a desired color. This process is repeated for each color so as to apply the colors of R, G, and B on the substrate, following which the resin is thermally hardened, thus forming a colored layer on the substrate.
A fourth color filter manufacturing method is the printing method. The printing method involves printing with a pigment dispersed in a thermally hardening resin three times so as to color the colors for R, G, and B, following which the resin is thermally hardened, thus forming a colored layer on the substrate.
Each of the above methods usually is followed by forming a protective layer on the surface of the colored layer.
All four of these methods share one point: that the same process must be performed three times in order to color the three colors R, G, and B, which means that the great number of processes decreases yield, increases costs, and so forth, which are shortcomings that have been pointed out. Further, with the electrocoating method, the form of patterns which can be formed are limited, so application to TFT-type color liquid crystal displays is difficult. Also, the printing method has poor resolution and smoothness, and thus has shortcomings in that producing finer patterns is difficult, and so forth.
In order to supplement these shortcomings, Japanese Patent Application Laid-Open No. 59-75205, Japanese Patent Application Laid-Open No. 63-235901, Japanese Patent Application Laid-Open No. 63-294503, and Japanese Patent Application Laid-Open No. 1-217302 disclose methods for forming a color filter using the ink jet method. These methods involve ejecting inks containing coloring matter of the three colors R (red), G (green), and B (blue), on a photo-transmitting substrate by the ink jet method, and drying the inks so as to form filter elements. With an ink jet method such as this, the filter elements for R, G, and B can be formed all at once, leading to marked simplification of the manufacturing process, and great reductions in costs.
Now, when forming color filters with the ink jet method, there is the need to position the head having multiple ink discharge orifices and the substrate in a highly precise manner. However, the above publications do not take into consideration the production aspects of mass-producing such color filters, and accordingly the color filters cannot be manufactured in a stable manner. That is to say, the above publications are insufficient with regard to mass-production of the color filters.
In order to improve such insufficiencies, Japanese Patent Application Laid-Open No. 9-49919 discloses positioning heads having multiple ink discharging orifices and the substrate in a highly precise manner, thereby improving the production of color filters. According to this publication, of the three RGB heads, one color head is used as a reference and the other two color heads are positioned relative to that head beforehand, and are fixed at the time of printing, so that positioning of heads having multiple ink discharging orifices and the substrate can be performed in a highly precise manner, thus improving production of color filters.
Now, recent advancements in liquid crystal device manufacturing technology have led to increased size of glass substrates and image size (i.e., color filter size), and finer pixels. Conventionally, the size of glass substrates has been around 360 mmxc3x97465 mm, but recently this has increased to around 550 mmxc3x97650 mm, 680 mmxc3x97880 mm, and 730 mmxc3x97920 mm. The screen size has also been increasing yearly in a corresponding manner, such as 10.4 inch, 12.1 inch, 13.3 inch, 14.1 inch, 15.0 inch, 17.0 inch, 18.0 inch, and 20.0 inch screens. Further, the number of pixels of the color filters has been increasing in the manner of VGA (640 xc3x97480), SVGA (800xc3x97600), XGA (1024xc3x97768), SXGA (1280xc3x971024), SXGA+ (1400xc3x971050), UXGA (1600xc3x971200), and QXGA (2048xc3x971536). Thus, color filters are increasing in resolution and fineness.
In the event of using such large-size substrates and manufacturing color filters for large-size screens with fine displays, the amount of time necessary for manufacturing each color filter is longer than that for conventional color filters with smaller screen sizes and lower resolution. An arrangement for realizing reduction in manufacturing time and further improving productivity can be conceived wherein a great number of heads for discharging ink of the same color are used. However, Japanese Patent Application Laid-Open No. 9-49919 only mentions using one head per color per head unit, and does not make description of what sort of head configuration would be used in the event that multiple heads of for the same color were to be used on one head unit.
In the event of manufacturing a color filter using multiple heads of the same color, the present inventor has found that simply using multiple heads would lead to increased time necessary for head positioning, which would counter the object of reduction in manufacturing time to be realized by the increased number of heads used, and accordingly improvement in the production of color filters would not be sufficiently accomplished. In other words, increasing the number of heads used would be meaningless if it requires a long time to position the heads relative to one another, and accordingly the present inventor has noted that a head unit having multiple heads of the same color must also comprise a mechanism wherein positioning of the heads relative to one another can be performed in a simple manner and particularly without taking much time. Note that the above description has been made with reference to an example of manufacturing a color filter, but the same can be used in manufacturing EL devices formed by applying self-illuminating material (EL light-emitting material) in recession surrounded by partitions provided upon a substrate. However, in the case of EL display devices, what is necessary is not a mechanism for positioning heads discharging ink of the same color relative to one another, but a mechanism for positioning heads discharging self-illuminating material which emits light of the same color; relative to one another. Further other than such color filters and EL display devices, the same can be used in manufacturing display device panels formed by discharging display material on a substrate.
The present invention has been made in consideration of the above problems, and accordingly it is an object thereof to provide a head unit, a manufacturing apparatus using the head unit for manufacturing display device panels (color filters, EL display devices, etc.), a manufacturing method thereof, a manufacturing method for liquid crystal display devices having color filters, and a manufacturing method for devices having the liquid crystal display devices, wherein, even in the event that the number of heads used is increased, prolonged periods of time are not necessary for adjusting the positions of the heads one with another, so as to reduce manufacturing time sufficiently, and wherein production of display device panels such as color filters and EL display devices is improved.
To this end, according to a first aspect of the present invention, a head unit used with an apparatus for manufacturing a panel for a display device comprising a plurality of display units, wherein the head unit and a substrate are scanned relatively while applying liquid to pixel areas on the substrate from the head unit, comprises: a first liquid discharging head comprising a first liquid discharging orifice row including multiple liquid discharging orifices; a second liquid discharging head comprising a second liquid discharging orifice row including multiple liquid discharging orifices; a head mounting unit for arraying the first liquid discharging head and the second liquid discharging head in the same direction such that the first liquid discharging orifice row and the second liquid discharging orifice row are positioned in the same direction; and position adjusting means for adjusting a relative position of the first liquid discharging head and the second liquid discharging head by moving at least one of the first liquid discharging head and the second liquid discharging head in the direction of the first and second liquid discharging orifice rows; wherein the position adjusting means effects adjusting such that a spacing between a first liquid discharging orifice of the first liquid discharging head and a first liquid discharging orifice of the second liquid discharging head is N times (wherein N is a natural number) the pitch of the liquid discharging orifices of the first liquid discharging head.
According to a second aspect of the present invention, a head unit used with an ink jet recording device which records by relatively scanning the head unit and a recording medium while applying ink onto the recording medium, comprises: a first ink jet head comprising a first ink discharging orifice row including multiple ink discharging orifices; a second ink jet head comprising a second ink discharging orifice row including multiple ink discharging orifices; a head mounting unit for arraying the first ink jet head and the second ink jet head in the same direction such that the first ink discharging orifice row and the second ink discharging orifice row are positioned in the same direction; and position adjusting means for adjusting a relative position of the first ink jet head and the second ink jet head by moving at least one of the first ink jet head and the second ink jet head in the direction of the first and second ink discharging orifice rows, wherein the position adjusting means effects adjusting such that a spacing between a first ink discharging orifice of the first ink jet head and a first ink discharging orifice of the second ink jet head is N times (wherein N is a natural number) the pitch of the ink discharging orifices of the first ink jet head.
According to a third aspect of the present invention, a display device panel manufacturing apparatus for manufacturing panels for a display device comprising a plurality of display units, wherein a head unit and a substrate are scanned relatively while applying liquid to pixel areas on the substrate, comprises: a head unit comprising a first liquid discharging head comprising a first liquid discharging orifice row including multiple liquid discharging orifices, a second liquid discharging head comprising a second liquid discharging orifice row including multiple liquid discharging orifices, a head mounting unit for arraying the first liquid discharging head and the second liquid discharging head in the same direction such that the first liquid discharging orifice row and the second liquid discharging orifice row are positioned in the same direction, and position adjusting means for adjusting a relative position of the first liquid discharging head and the second liquid discharging head by moving at least one of the first liquid discharging head and the second liquid discharging head in the direction of the liquid discharging orifice rows; scanning means for scanning the head unit and the substrate relatively; and control means for controlling such that liquid is discharged from the first and second liquid discharging heads of the head unit during the relative scanning by the scanning means so as to form a display portion on the substrate, wherein the position adjusting means effects adjusting before discharging of the liquid such that a spacing between a first liquid discharging orifice of the first liquid discharging head and a first liquid discharging orifice of the second liquid discharging head is N times (wherein N is a natural number) the pitch of the liquid discharging orifices of the first liquid discharging head.
According to a fourth aspect of the present invention, a manufacturing method for manufacturing panels for a display device comprising a plurality of display units, wherein a head unit comprising a plurality of liquid discharging heads and a substrate are scanned relatively while applying liquid to pixel areas on the substrate from the liquid discharging heads, comprises: an adjusting step for adjusting a head unit comprising a first liquid discharging head comprising a first liquid discharging orifice row including multiple liquid discharging orifices, a second liquid discharging head comprising a second liquid discharging orifice row including multiple liquid discharging orifices, a head mounting unit for arraying the first liquid discharging head and the second liquid discharging head in the same direction such that the first liquid discharging orifice row and the second liquid discharging orifice row are positioned in the same direction, and position adjusting means for adjusting a relative position of the first liquid discharging head and the second liquid discharging head by moving at least one of the first liquid discharging head and the second liquid discharging head in the direction of the liquid discharging orifice rows; a scanning step for scanning the head unit and the substrate relatively; and a forming step for forming the display portion on the substrate by discharging liquid from the first and second liquid discharging heads of the head unit during the relative scanning, wherein the adjusting step is effected with the position adjusting means before the forming step, such that a spacing between a first liquid discharging orifice of the first liquid discharging head and a first liquid discharging orifice of the second liquid discharging head is N times (wherein N is a natural number) the pitch of the liquid discharging orifices of the first liquid discharging head.
Also, according to the present invention, a method for manufacturing a liquid crystal display device comprising a color filter manufactured by relatively scanning a head unit having a plurality of ink jet heads and a substrate while applying ink to the substrate from the ink jet heads, thereby coloring a filter element which functions as the color filter, comprises: a step for preparing a color filter manufactured by the manufacturing method according to the fourth aspect; and a step for sealing a liquid crystal compound between the prepared color filter and an opposing substrate facing the color filter.
Further, according to the present invention, a method for manufacturing an apparatus comprising a liquid crystal display device having a color filter manufactured by relatively scanning a head unit having a plurality of ink jet heads and a substrate while applying ink to the substrate from the ink jet heads, thereby coloring a filter element which functions as the color filter, comprises: a step for preparing a color filter manufactured by the manufacturing method according to the fourth aspect; a step for sealing a liquid crystal compound between the prepared color filter and an opposing substrate facing the color filter so as to manufacture the liquid crystal display device; and a step for connecting to the liquid crystal display device image signal supplying means for supplying image signals to the liquid crystal display device.
Further objects, features and advantages of the present invention will become apparent from the following description of the preferred embodiments with reference to the attached drawings.